UIScaler will automatically calculate the optimal scale for your resolution, so you don't have to. How is this different from similar addons? This is particularly useful for Mac users who can easily switch back and forth between fullscreen and windowed mode. It also takes into account the fact that changing the UI scale while in combat might cause taint, and thus delays doing so until combat is over. While this is useful for anyone to get a true 1:1 pixel ratio, the main purpose of this addon is to support higher resolutions normally unsupported by Blizzard by allowing the UI to be scaled below the minimum threshold of 64%. This addon calculates the optimal UI scale for your resolution and automatically applies it when you log in, or the UI scale is changed by the game (or you).